Mystery viruses found in raw sewage

Thousands of novel, undiscovered viruses, some of which could affect human health, are believed to be hiding in raw sewage, new research shows.

There are roughly 1.8 million species of organisms on the planet, and each one is host to untold numbers of unique viruses, but only about 3,000 have been identified to date.

To explore this diversity and to better characterize the unknown viruses, researchers developed techniques to look for genetic signatures of novel viruses in various locations in North America, Europe, and Africa and found signatures from 234 known viruses, representing 26 different families of viruses in raw sewage, making it home to the most diverse array of viruses yet found.

“What was surprising was that the vast majority of viruses we found were viruses that had not been detected or described before,” says Roger Hendrix, professor of biological sciences at University of Pittsburgh.